Not applicable.
Not applicable.
1. Field of the Invention
The invention relates to rollforming machines and, more particularly, to adjustable rollforming machines for forming components from materials of different thicknesses and rollforming machines having the capability to overbend the component being formed.
2. Description of the Invention Background
Rollforming is a well-know process of bending a continuous strip or cut to length strip of metal through a series of shaped rolls. Common rollforming processes gradually form a strip of metal into a predetermined shape. The shapes may include, for example, generally C-shaped cross sections or generally U-shaped cross sections, or may include relatively complex formations being formed along the length of the material.
Rollforming processes are widely used because they are regarded as being a highly efficient means for continuously forming metal strip. Any number of other operations may be performed while the metal is taking shape. These other operations may include, for example, punching, tabbing, cutting to length, perforating, drawing, lancing, embossing, knurling, edge conditioning and curving. One particular benefit of rollforming is that strength and function are added to the metal as a result of the rollforming process. Rollforming, therefore, provides for many advantages in comparison to other known processes for forming metal materials.
The marketplace for shaped, rollformed sections has expanded into virtually every field of industry thereby replacing other known processes such as extrusions, brake forming and punch press operations in the areas such as the aircraft industry and the automotive industry. Another industry that heavily relies on rollforming is the architectural industry, and more specifically, the metal frame construction industry. As an alternative to traditional wood construction components, a variety of metal frame constructions and associated components have been developed for use in the residential and/or commercial building industry. The components needed for the metal frame construction industry are greatly varied and thus can be time consuming and expensive to manufacture using conventional rollforming techniques. For example, the needed components must be manufactured in an assortment of sizes, gauges and shapes depending upon the particular need for an assortment of different residential and/or commercial structures in which the components will be utilized. In addition, such components must be manufactured to relatively close tolerances to ensure that they will fit together properly and can easily be assembled and installed.
Rollforming machines for producing components used, for example, in the metal frame construction industry, are well known and typically include a plurality of sets of forming rolls arranged in upper and lower pairs and spaced apart along the length of the rollforming machine on rollforming support stands. As is also well known, the forming rolls at one stand will produce a continuous formation in the material and the forming rolls of the next stand will produce another formation, or for example, increase the angle of the formation which has already been started at the previous stand and so on. Examples of such rollforming machines are disclosed, in U.S. Pat. Nos. 5,970,764 and 5,829,295.
When rollforming a strip of metal to produce a component, it is advantageous for the rollforming machine to be capable of working on materials of different thicknesses, also referred to as the xe2x80x9cgaugexe2x80x9d of the material in the metals industry. In order to achieve this flexibility of working on materials of different thicknesses, early rollforming machines required that the forming rolls be replaced entirely or substantially changed when it was desirable to form a material having a different thickness. As can be appreciated, this practice of completely replacing the forming rolls was very costly in terms of material costs to provide numerous different forming rolls, labor costs for the added time of installing and reinstalling the forming rolls, and the manufacturing costs in view of the time that the rollforming machine could not be in operation during replacement of the forming rolls. More modern rollforming machines provide for automatic adjustment of the forming rolls to accommodate the materials of different thicknesses. For example, the aforementioned U.S. Pat. No. 5,970,764 discloses a first rack and pinion arrangement in combination with an eccentrically mounted shaft for adjusting the clearance between forming rolls in a first plane and a second rack and pinion arrangement in combination with an additional eccentrically mounted shaft for adjusting the clearance between the forming rolls in a second plane. While apparently effective at adjusting the clearance between the forming rolls for materials of different thicknesses, such an arrangement still has many disadvantages and shortcomings. For example, many mechanical parts are necessary to achieve the desired adjustment resulting in increased costs for manufacturing and maintaining the rollforming machine, and also resulting in the increased likelihood of mechanical failure leading to down time and lost operating revenue for the rollforming machine. In addition, such arrangement is apparently unable to accurately and consistently maintain the required tolerances when rollforming a component.
When performing a rollforming process to produce a component of a particular shape, it is desirable for the component to maintain the desired shape after the rollforming process is completed and the component exits the rollforming machine. One problem that can occur when rollforming products is commonly referred to in the rollforming industry as xe2x80x9cspringbackxe2x80x9d. The bending process that takes place during rollforming is a complex process which seeks to avoid stress concentration at the points of bending. Because the material being rollformed has a modulus of elasticity, the material tries to assume a shape having a bend of lesser extent than was desired. Therefore, springback is generally defined as the elastic recovery of metal after a stress has been applied. Other properties of the metal which may affect and contribute to springback are, for example, tensile strength, yield strength and Rockwell hardness. As can be appreciated, the amount of springback that may occur will vary for different materials and for different shapes depending upon the degree of bending.
One solution to correcting springback is to rework the rollformed component to mitigate the effects of the springback. However, to rework the component greatly increases the unit cost for the component and, therefore, is not an effective solution. Another solution to springback is to employ additional rollforming stands on the rollforming machine that include forming rolls cut to specific angles in order to overbend the component once the desired shape has been achieved. However, this also greatly increases the costs of rollforming by requiring additional rollforming stands and increased material and labor costs to install and replace the forming rolls depending upon the particular angle that is needed in order to achieve the necessary overbend to compensate for the springback.
There is identified, therefore, a need for an improved rollforming machine that overcomes limitations, shortcomings and disadvantages of known rollforming machines.
There is also a need for an improved rollforming machine that is capable of accommodating materials of different thicknesses.
There is a further need for an improved rollforming machine that can be easily and efficiently adjusted for materials of different thicknesses and profiles.
There is a further need for an improved rollforming machine that is capable of producing a component of a desired shape or configuration wherein the component maintains the desired shape or configuration once the rollforming is completed and the component is removed from the rollforming machine.
Still another need exists for an improved rollforming machine with effective overbending capabilities for ensuring that the component formed by the rollforming machine maintains the desired shape or configuration once the rollforming is completed and the component is removed from the rollforming machine.
A need also exists for an improved rollforming machine that includes overbend capabilities wherein the desired and necessary amount of overbending can easily be adjusted and maintained while running production and during non-production.
The embodiments of the invention meet the above-identified needs, as well as other needs, as will be more fully understood following a review of this specification and drawings.
An embodiment of the invention includes a rollforming apparatus comprising a moveable support stand, a first forming roll, a second forming roll and a third forming roll. The first forming roll is rotatably mounted to a first spindle, wherein the first spindle is moveably connected to the support stand to provide for angular movement of the first forming roll. The second forming roll is mounted to a second spindle that extends through a central aperture defined by the first forming roll. The second spindle is moveably connected to the support stand to provide for movement of the second forming roll relative to the angular movement of the first forming roll. The third forming roll is rotatably supported by the support stand for movement therewith.
The rollforming apparatus may be utilized in conjunction with a rollforming machine that is structured and arranged to form components of different shapes and configurations, such as, for example, components having a generally C-shaped cross section, components having a generally U-shaped cross section or components with other cross sections as may be needed for particular applications. Advantageously, the first, second and third forming rolls of the rollforming apparatus are structured and arranged to perform, for example, overbending of the component to counter the effects of springback that may occur during the rollforming process.
A further embodiment of the invention includes a method of forming components of different shapes and configurations, such as, for example, a component having a generally C-shaped cross section, a component having a generally U-shaped cross section or a component having other cross sections depending upon the particular shape needed for a particular application of the component. The method includes feeding a sheet or coil of material to a rollforming station structured and arranged to form a portion of the component. The method also includes feeding the sheet of material to an additional rollforming station having a plurality of forming rolls supported by a plurality of spindles. The method further includes adjusting the position of at least one of the forming rolls resulting in moving the position of at least one of the spindles. Advantageously, the method may further include employing the roll station having a plurality of forming rolls supported by a plurality of spindles for overbending of a sheet of material to compensate for springback conditions that may develop in the component being formed.
An additional embodiment of the invention includes a rollforming apparatus comprising a support stand, a forming roll supported on a spindle, an adjustment block and a slide assembly. The spindle is rotatably secured to the adjustment block. The slide assembly is in cooperative engagement with the support stand and the adjustment block to provide movement of the forming roll axially along an axis of rotation of the spindle and transversely to the axis of rotation of the spindle.
The slide assembly may include an inner gage block mounted to the adjustment block and an outer gage block mounted to the support stand. The slide assembly may further include a rail member and a bearing member such that one of the rail member and the bearing member is attached to the inner gage block and the other of the rail member and the bearing member is attached to the outer gage block. The rail member and the bearing member are positioned for cooperative engagement to facilitate movement between the support stand and adjustment block to provide for movement of the forming roll. Advantageously, the rollforming apparatus provides for easy and efficient adjustment of the forming roll for materials of different thicknesses.
In another embodiment of the invention, the rollforming apparatus having a support stand, a forming roll supported on a spindle, an adjustment block and a slide assembly may be utilized in conjunction with a rollforming machine having a plurality of rollforming stations to form a component of a desired shape and configuration.
An additional embodiment of the invention includes a method of forming a component that includes feeding a sheet or coil of material to a rollforming station having a forming roll supported by a spindle rotatably secured to an adjustment block to form the component. The method also includes adjusting the position of the forming roll by employing a slide assembly in cooperative engagement with the adjustment block to facilitate movement of the forming roll in a direction that is the resultant of normal and axial components of motion of the spindle.